The present invention relates in general to an air blowing system including an air blowing device and a duct that guides air blown by the air blowing device and relates in particular to an air blowing system included in a copying machine, a multi-function device, a printer, or any other like image forming apparatus that forms an image on a recording sheet, for example, by an electrophotographic image forming method.
Air blowing systems including an air blowing device and a duct that guides air blown by the air blowing device have disadvantages related to unwanted noise produced by the air flow as detailed below.
For example, a ventilation section is disposed downstream of a duct in terms of a direction in which air is blown by the air blowing device (“air blowing direction”) so that the air blown by the air blowing device strikes and passes through the ventilation section. Specifically, an image forming apparatus including such an air blowing system typically vents air out of the image forming apparatus by guiding the air from the air blowing device through the duct and the ventilation section of the image forming apparatus. A specific example of the ventilation section is an opening section with an opening being formed through an exterior member of the image forming apparatus (e.g., an opening section with a plurality of slits). Another example is a filter (e.g., a purification filter that removes dust, toner, and other fine particles or an ozone filter that removes ozone).
The air blown by the air blowing device, when it passes through the ventilation section in the air blowing system, produces an unpleasant whistling sound, disturbing the user.
In the same type of air blowing system with an air blowing device and a duct, the air blown by the air blowing device causes the duct to bend periodically (vibrate) when the air passes through the duct. The vibration in turn causes resonance and produces an unpleasant resonating sound, disturbing the user.
In relation to these problems, Japanese Patent Application Publication, Tokukai, No. 2001-166622 discloses a duct extending from a single air blowing port and forking into two branch air paths. The two air paths of the duct are separated from each other by ribs.
The duct and ribs of Japanese Patent Application Publication, Tokukai, No. 2001-166622, however, are not sufficiently capable of reducing the whistling sound produced when the air blown by the air blowing device passes through the ventilation section, because the air paths are separated simply by ribs.
The simple separation of air paths by ribs of Japanese Patent Application Publication, Tokukai, No. 2001-166622 is also not sufficiently capable of reducing the resonating sound produced by the resonance of the duct that bends periodically (vibrates) when the air blown by the air blowing device passes through the duct.
Accordingly, the present invention has an object to provide an air blowing system and an image forming apparatus including the air blowing system. This air blowing system includes an air blowing device and a duct that guides air blown by the air blowing device. The air blowing system is also capable of reducing unwanted noise produced by the air flow (specifically, the whistling sound produced when the air blown by the air blowing device passes through the ventilation section and the resonating sound produced by the resonance of the duct that bends periodically (vibrates) when the air blown by the air blowing device passes through the duct).